Tatooine Ghost (Possible spoilers)

Ok. This could probably go under the Lit Board but since I spend most of my time here, and There is some questions I would Like answered, I will post it here. Lock me What ever.

So on the new release list I came across the title of a new EU book in the middle of the NJO that isn't prequil material. Which I am happy to see. The New Republic is my Favroite Era. Judging by the Title, It will have a lot to do with The Skywalker family. Tatooine Ghost is pretty much self explainable. So This brings me to my questions. How much do Luke and Leia really know about there family? And How much is there to learn?

Actually Wraith Leader, Tatooine Ghost is a Han/Leia adventure and takes place shortly after they're married. Chewie is supposed to have a big role and Luke apparently has a small role, but it's basically about Han and Leia. Here is the book synopsis:

The past haunts Princess Leia as she looks forward to an uncertain future. The four-year old New Republic continues to grow, as does Leia's love for her husband, Han Solo. But despite his wants, Leia is determined not to have children, for fear of the uncertainty of the Skywalker bloodline.

An artifact from Alderaan containing secret codes used by the New Republic resurfaces at a shady Mos Espa auction, and Han and Leia voyage to Tatooine to secure it. While on the desert planet, Leia finds evidence of her father's past that cause her to rethink some of her firmest held beliefs.

And in case you're interested you can see the book cover at the link below.